package com.nowcoder.nowcodercommunity.service;

import com.nowcoder.nowcodercommunity.entity.User;
import com.nowcoder.nowcodercommunity.util.CommunityConstant;
import com.nowcoder.nowcodercommunity.util.RedisKeyUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.SessionCallback;
import org.springframework.stereotype.Service;

import javax.validation.constraints.AssertFalse;
import java.util.*;

@Service
public class FollowService  implements CommunityConstant {
    @Autowired
    private RedisTemplate redisTemplate;

    @Autowired
    private UserService userService;

    public void follow(int userId,int entityType,int entityId){
        redisTemplate.execute(new SessionCallback() {
            @Override
            public Object execute(RedisOperations operations) throws DataAccessException {
                String followeeKey= RedisKeyUtil.getFolloweeKey(userId,entityType);
                String followerKey=RedisKeyUtil.getFollowerKey(entityType,entityId);

                operations.multi();
                operations.opsForZSet().add(followeeKey,entityId,System.currentTimeMillis());
                operations.opsForZSet().add(followerKey,userId,System.currentTimeMillis());

                return operations.exec();
            }
        });
    }
    public void unfollow(int userId,int entityType,int entityId){
        redisTemplate.execute(new SessionCallback() {
            @Override
            public Object execute(RedisOperations operations) throws DataAccessException {
                String followeeKey= RedisKeyUtil.getFolloweeKey(userId,entityType);
                String followerKey=RedisKeyUtil.getFollowerKey(entityType,entityId);

                operations.multi();
                operations.opsForZSet().remove(followeeKey,entityId);
                operations.opsForZSet().remove(followerKey,userId);

                return operations.exec();
            }
        });
    }


    // 查询关注实体的数量
    public long findFolloweeCount(int userId,int entityType){
        String followeeKey=RedisKeyUtil.getFolloweeKey(userId,entityType);
        return redisTemplate.opsForZSet().zCard(followeeKey);
    }
    // 查询实体的粉丝数量
    public long findFollowerCount(int entityType,int entityId){
        String followerKey=RedisKeyUtil.getFollowerKey(entityType, entityId);
        return redisTemplate.opsForZSet().zCard(followerKey);
    }
    // 查询当前用户是否已关注该实体
    public boolean hasFollowed(int userId,int entityType,int entityId){
        String followeeKey=RedisKeyUtil.getFolloweeKey(userId, entityType);
        return redisTemplate.opsForZSet().score(followeeKey,entityId) != null;
    }

    // 查询某用户关注的人
    public List<Map<String,Object>> findFollowees(int userId,int offset,int limit){
        String followeeKey = RedisKeyUtil.getFolloweeKey(userId,ENTITY_TYPE_USER);
        Set<Integer> targetIds=redisTemplate.opsForZSet().reverseRange(followeeKey,offset,offset+limit-1);
        if(targetIds == null){
            return null;
        }
        List<Map<String,Object>> list=new ArrayList<>();
        for (Integer targetId : targetIds) {
            Map<String,Object> map=new HashMap<>();
            User user=userService.findUserById(targetId);
            map.put("user",user);
            Double score=redisTemplate.opsForZSet().score(followeeKey,targetId);
            map.put("followTime",new Date(score.longValue()));
            list.add(map);
        }

        return list;
    }
    //查询某用户的粉丝
    public List<Map<String,Object>>  findFollowers(int userId,int offset,int limit){
        String followerKey = RedisKeyUtil.getFollowerKey(ENTITY_TYPE_USER,userId);
        Set<Integer> targetIds=redisTemplate.opsForZSet().reverseRange(followerKey,offset,offset+limit-1);
        if(targetIds == null){
            return null;
        }

        List<Map<String,Object>> list=new ArrayList<>();
        for (Integer targetId : targetIds) {
            Map<String,Object> map=new HashMap<>();
            User user=userService.findUserById(targetId);
            map.put("user",user);
            Double score=redisTemplate.opsForZSet().score(followerKey,targetId);
            map.put("followTime",new Date(score.longValue()));
            list.add(map);
        }

        return list;

    }

}
